San Diego, California (CNN) -- A moderate earthquake followed by dozens of smaller ones rattled Southern California Monday evening, just north of the Mexican border, the U.S. Geological Survey reported.
The magnitude 5.7 quake struck at 9:26 p.m. local time and was centered 70 miles east of San Diego.
"Since the 5.7 occurred, we've had another larger series of aftershocks occurring," said geophysicist Amy Vaughan of the USGS in Golden, Colorado. "We've had about 40 occurring since that with the largest being about a 4.5."
The main jolt and subsequent aftershocks have been felt across a large area in the region, Vaughan said.
"We've had over 12,000 'felt reports' coming in from most of Southern California, parts of Arizona and parts of Baja California," Vaughan said.
Authorities throughout Southern California reported no damage in the immediate aftermath of the earthquake.
"Were this a 7.5 it would be a different story probably, but because it's a 5.7 occurring in this area and also not directly in a large metropolitan area, like it's not downtown LA or downtown San Diego, helps as well," Vaughan said.
CNN Radio's Shelby Erdman contributed to this report.